35-10
MPC860 PowerQUICC UserÕs Manual
MOTOROLA
Part V. The Communications Processor Module
If the error vector is taken, no CISR bit is set. All undeÞned CISR bits return zeros when
read. The extent to which CPM interrupts can interrupt one another is controlled by
selectively clearing the CISR. A new interrupt is processed if it has a higher priority than
the highest priority interrupt having its CISR bit set. Thus, if an interrupt routine sets the
external interrupt enable bit in the core (MSR[EE]) and clears its CISR bit at the beginning
of the interrupt routine, a lower priority interrupt can interrupt a higher one if the lower
priority interrupt has higher priority than any other CISR bits that are currently set.
Therefore, the interrupt service routine should clear its CISR bit at the end.
35.5.5 CPM Interrupt Vector Register (CIVR)
The CPM interrupt vector register (CIVR) is used to identify an interrupt source. The core
uses the IACK bit to acknowledge an interrupt. CIVR can be read at any time.
35-4 describes CIVR Þelds. Section
35.6, ÒInterrupt Handler ExampleÑ
Single-Event Interrupt Source,Ó and Section
35.7, ÒInterrupt Handler ExampleÑ
Multiple-Event Interrupt Source,Ó show how CIVR Þelds are used.
35.6 Interrupt Handler ExampleÑSingle-Event
Interrupt Source
In this example, the CPIC hardware clears CIPR[PC6] during the interrupt acknowledge
cycle. The following steps show how to handle an interrupt source without multiple events.
1. Set CIVR[IACK].
2. Read CIVR[VN] to determine the vector number for the interrupt handler.
3. Handle the interrupt event indicated through the port C6 signal.
4. Clear CISR[PC6].
5. Execute the rfi instruction.
Bit
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Field
VN
0
IACK
Reset
0000_00000_0000_0000
R/w
R/W
Address
0x930
Figure 35-5. CPM Interrupt Vector Register (CIVR)
Table 35-4. CIVR Field Descriptions
Bits
Name
Description
0Ð4
VN
Vector number. IdentiÞes the interrupt source. These values are listed in Table 35-2.
5Ð14
Ñ
Reserved. Writing to bits 5-15 has no effect because they are always read as zeros.
15
IACK
Interrupt acknowledge. When the core sets IACK, CIVR[VN] is updated with a 5-bit vector
corresponding to the sub-block with the highest current priority. IACK is cleared after one clock cycle.
Summary of Contents for MPC860 PowerQUICC
Page 3: ...MPC860UM AD 07 98 REV 1 MPC860 PowerQUICC ª UserÕs Manual ...
Page 36: ...xxxvi MPC860 PowerQUICC UserÕs Manual MOTOROLA CONTENTS Paragraph Number Title Page Number ...
Page 78: ...I iv MPC860 PowerQUICC UserÕs Manual MOTOROLA Part I Overview ...
Page 88: ...1 10 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part I Overview ...
Page 114: ...3 16 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part I Overview ...
Page 226: ...8 32 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part II PowerPC Microprocessor Module ...
Page 262: ...9 36 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part II PowerPC Microprocessor Module ...
Page 274: ...III iv MPC860 PowerQUICC UserÕs Manual MOTOROLA Part III Configuration ...
Page 320: ...12 12 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part III Configuration ...
Page 325: ...MOTOROLA Part IV Hardware Interface IV v Part IV Hardware Interface ...
Page 326: ...IV vi MPC860 PowerQUICC UserÕs Manual MOTOROLA Part IV Hardware Interface ...
Page 352: ...13 26 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part IV Hardware Interface ...
Page 394: ...14 42 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part IV Hardware Interface ...
Page 426: ...15 32 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part IV Hardware Interface ...
Page 530: ...17 26 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part IV Hardware Interface ...
Page 632: ...21 44 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 660: ...22 28 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 708: ...24 24 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 748: ...27 20 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 846: ...31 20 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 914: ...35 12 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 948: ...36 34 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 998: ...37 48 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part VI Debug and Test ...
Page 1016: ...A 10 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
Page 1024: ...B 8 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
Page 1030: ...C 6 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
Page 1086: ...Glossary 12 MPC860 PowerQUICC UserÕs Manual MOTOROLA ...
Page 1106: ......